Early-life obesity and adulthood colorectal cancer risk: a meta-analysis

Comparison of laparoscopic and open surgery for colorectal malignancy in obese patients: a propensity score-weighted cohort study

BACKGROUND

Insufficient evidence exists to ascertain the long-term prognosis in patients with obesity undergoing laparoscopic surgery versus open surgery for colorectal cancer.

METHODS

Employing an institutional database from 2009 to 2019, we assessed individuals with a BMI of greater than or equal to 30 kg/m 2 who underwent surgery for primary stage I-III colorectal adenocarcinoma. The authors used propensity score-weighted analysis to compare short-term and oncologic outcomes between laparoscopic and open surgical approaches.

RESULTS

This study enrolled 473 patients (open vs. laparoscopic surgery: 220 vs. 253; median follow-up period, 60 months). The laparoscopy group showed a significantly longer operative time (252 vs. 212 min), a higher anastomotic-leakage rate (5.14% vs. 0.91%), and a greater proportion of Clavien-Dindo class greater than III complications (5.93% vs. 1.82%). The open group showed a higher wound infection rate (7.27% vs. 3.16%) and a higher readmission rate (6.36% vs. 2.37%). After propensity score weighting, laparoscopy was inferior to open surgery in terms of long-term overall survival (hazard ratio: 1.43), disease-free survival (1.39), and recurrence rate (21.1% vs. 14.5%). In the subgroup analysis, female patients, older individuals, stage III patients, patients with rectal cancer, and those who underwent surgery after 2014 showed inferior long-term outcomes after laparoscopy.

CONCLUSIONS

Laparoscopic colorectal cancer surgery for patients with obesity requires significant caution. Despite good short-term outcomes, this procedure is associated with hidden risks and poor long-term prognoses. In female patients, older individuals, stage III patients, patients with rectal cancer, and those treated in the late surgery era subgroups, caution is advised when performing laparoscopic surgery.

Changing epidemiology of colorectal cancer - birth cohort effects and emerging risk factors

Incidence and mortality of colorectal cancer (CRC) are increasing worldwide, suggesting broad changes in the epidemiology of CRC. In this Review, we discuss the changes that are becoming evident, including trends in CRC incidence and mortality by age and birth cohort, and consider the contributions of early-life exposures and emerging risk factors to these changes. Importantly, incidence of CRC has increased among people born since the early 1950s in nearly all regions of the world. These so-called birth cohort effects imply the involvement of factors that influence the earliest stages of carcinogenesis and have effects across the life course. Accumulating evidence supports the idea that early-life exposures are important risk factors for CRC, including exposures during fetal development, childhood, adolescence and young adulthood. Environmental chemicals could also have a role because the introduction of many in the 1950s and 1960s coincides with increasing incidence of CRC among people born during those years. To reverse the expected increases in the global burden of CRC, participation in average-risk screening programmes needs to be increased by scaling up and implementing evidence-based screening strategies, and emerging risk factors responsible for these increases need to be identified.

[Obesity and Colorectal Cancer]

The prevalence of obesity has increased significantly worldwide, and this trend is likely to continue in the coming years. There is substantial evidence that obesity plays a crucial role in the development of colorectal cancer. Epidemiological data have consistently demonstrated a correlation between obesity and colorectal cancer. Insulin resistance, hyperinsulinemia, chronic inflammation, altered levels of growth factors, adipocytokines, and various hormones are plausible biological mechanisms. In addition, obesity has been shown to have an impact on recurrence, treatment success, and overall survival. There are some reports, although the evidence is not conclusive, that weight loss and lifestyle changes such as dietary modification and physical activity can reduce the risk of colorectal cancer. The understanding that obesity is a potentially modifiable risk factor that can affect the incidence and prognosis of colorectal cancer is crucial knowledge that can have an impact on the prevention and treatment of the condition.

Body size over the adult life course and the risk of colorectal cancer among postmenopausal women

OBJECTIVE

To assess the associations among several anthropometric measures, as well as BMI trajectories and colorectal cancer (CRC) risk in older women.

DESIGN

Prospective cohort study.

SETTING

Forty clinical centres in the USA.

PARTICIPANTS

Totally, 79 034 postmenopausal women in the Women's Health Initiative Observational Study.

RESULTS

During an average of 15·8 years of follow-up, 1514 CRC cases were ascertained. Five BMI trajectories over 18-50 years of age were identified using growth mixture model. Compared with women who had a normal BMI at age 18, women with obesity at age 18 had a higher risk of CRC (HR 1·58, 95 % CI 1·02, 2·44). Compared with women who kept relatively low normal body size during adulthood, women who progressed from normal to obesity (HR 1·29, 95 % CI 1·09, 1·53) and women who progressed from overweight to obesity (HR 1·37, 95 % CI 1·13, 1·68) had higher CRC risks. A weight gain > 15 kg from age 18 to 50 (HR 1·20, 95 % CI 1·04, 1·40) and baseline waist circumference > 88 cm (HR 1·33, 95 % CI 1·19, 1·49) were associated with higher CRC risks, compared with stable weight and waist circumference ≤ 88 cm, respectively.

CONCLUSION

Women who have a normal weight in early adult life and gain substantial weight later, as well as those who are persistently heavy over adulthood, demonstrated a higher risk of developing CRC. Our study highlights the importance of maintaining a healthy body weight over the life course for reducing the risk of developing CRC in women.

Association of changes in obesity and abdominal obesity status with early-onset colorectal cancer risk: a nationwide population-based cohort study

Background and aims

The incidence of early-onset colorectal cancer (EO-CRC, diagnosed before 50 years of age) has increased in recent decades. The aim of this study was to investigate the association between changes in obesity status and EO-CRC risk.

Methods

From a nationwide population-based cohort, individuals <50 years old who participated in the national health checkup program in both 2009 and 2011 were included. Obesity was defined as a body mass index ≥25 kg/m². Abdominal obesity was defined as a waist circumference ≥ 90 cm in men and ≥ 85 cm in women. Participants were classified into 4 groups according to the change in obesity (normal/normal, normal/obese, obese/normal, persistent obese) and abdominal obesity (normal/normal, normal/abdominal obesity, abdominal obesity/normal, persistent abdominal obesity) status. Participants were followed up until 2019 and censored when they became 50 years old.

Results

Among 3,340,635 participants, 7,492 patients were diagnosed with EO-CRC during 7.1 years of follow-up. The risk of EO-CRC was higher in the persistent obesity and persistent abdominal obesity groups than in the normal/normal groups (hazard ratio (HR) [95% confidence interval (CI)] = 1.09 [1.03-1.16] and 1.18 [1.09-1.29], respectively). Participants with both persistent obesity and abdominal obesity had a higher EO-CRC risk than those in the normal/normal groups for both [HR (95% CI) = 1.19 (1.09-1.30)].

Conclusion

Persistent obesity and persistent abdominal obesity before the age of 50 are associated with a slightly increased risk of EO-CRC. Addressing obesity and abdominal obesity in young individuals might be beneficial in reducing the risk of EO-CRC.

Association of Overweight, Obesity, and Recent Weight Loss With Colorectal Cancer Risk

Importance

Overweight and obesity, conditions with rising prevalence in many countries, are associated with increased colorectal cancer (CRC) risk. However, many patients with CRC lose weight before diagnosis, which may lead the association to be underestimated.

Objective

To evaluate the association of body mass index (BMI) and weight change with CRC risk when considering BMI at different time frames, with the intention to account for prediagnostic weight loss.

Design, Setting, and Participants

This population-based case-control study was conducted in southwestern Germany between 2003 and 2021. Cases with a first diagnosis of CRC and controls (frequency matched by age, sex, and county) with comprehensive risk factor information and self-reported weight at different time points were included. Data were analyzed between October 2022 and March 2023.

Exposure

BMI and weight change at different time frames before the time of diagnosis (cases) or recruitment (controls).

Main Outcomes and Measures

Association of BMI and weight change at various points in time before and up to diagnosis with CRC, assessed by multivariable logistic regression with comprehensive confounder adjustment.

Results

A total of 11 887 participants (6434 CRC cases, 5453 controls; median [IQR] age, 69 [61-77] years; 7173 male [60.3%]) were included. At the time of diagnosis, 3998 cases (62.1%) and 3601 controls (66.0%) were overweight or obese, suggesting an inverse association between excess weight and CRC risk. Conversely, we found significant positive associations of overweight (adjusted odds ratio [aOR], 1.27; 95% CI, 1.03-1.56), obesity (aOR, 2.09; 95% CI, 1.61-2.70), and a 5-unit increase in BMI (aOR, 1.35; 95% CI, 1.21-1.50) with CRC risk when using BMI measured 8 to 10 years before diagnosis. High BMI as a risk factor for CRC was increased as earlier periods before diagnosis were examined, with the association being particularly pronounced using BMI at least 8 years before diagnosis. An opposite trend was found for the association of weight loss (at or exceeding 2 kg) with CRC, with the greatest effect sizes occurring for weight loss within 2 years before diagnosis (aOR, 7.52; 95% CI, 5.61-10.09), and gradually decreased for earlier intervals.

Conclusions and Relevance

In this population-based case-control study, accounting for substantial prediagnostic weight loss further highlighted the association of overweight and obesity with CRC risk.

Why Does Obesity as an Inflammatory Condition Predispose to Colorectal Cancer?

Obesity is a complex and multifactorial problem of global importance. Additionally, obesity causes chronic inflammation, upregulates cell growth, disturbs the immune system, and causes genomic instability, increasing the risk of carcinogenesis. Colorectal cancer is one of the most common cancers, and it has become a global problem. In 2018, there were around 1.8 million new cases and around 881,000 deaths worldwide. Another risk factor of colorectal cancer associated with obesity is poor diet. A Western diet, including a high intake of red and processed meat and a low consumption of whole grains, fruits, vegetables, and fiber, may increase the risk of both colorectal cancer and obesity. Moreover, the Western diet is associated with a proinflammatory profile diet, which may also affect chronic low-grade inflammation. In fact, people with obesity often present gut dysbiosis, increased inflammation, and risk of colorectal cancer. In this article, the association between obesity and colorectal cancer is discussed, including the most important mechanisms, such as low-grade chronic inflammation, gut dysbiosis, and poor diet.

Is the association of overweight and obesity with colorectal cancer underestimated? An umbrella review of systematic reviews and meta-analyses

Although high body-mass index (BMI) is associated with increased risk of developing colorectal cancer (CRC), many CRC patients lose weight before diagnosis. BMI is often reported close to diagnosis, which may have led to underestimation or even reversal of direction of the BMI-CRC association. We aimed to assess if and to what extent potential bias from prediagnostic weight loss has been considered in available epidemiological evidence. We searched PubMed and Web of Science until May 2022 for systematic reviews and meta-analyses investigating the BMI-CRC association. Information on design aspects and results was extracted, including if and how the reviews handled prediagnostic weight loss as a potential source of bias. Additionally, we analyzed how individual cohort studies included in the latest systematic review handled the issue. Overall, 18 reviews were identified. None of them thoroughly considered or discussed prediagnostic weight loss as a potential source of bias. The majority (15/21) of cohorts included in the latest review did not exclude any initial years of follow-up from their main analysis. Although the majority of studies reported having conducted sensitivity analyses in which initial years of follow-up were excluded, results were reported very heterogeneously and mostly for additional exclusions of 1-2 years only. Where explicitly reported, effect estimates mostly increased with increasing length of exclusion. The impact of overweight and obesity on CRC risk may be larger than suggested by the existing epidemiological evidence.

Separating the effects of early and later life adiposity on colorectal cancer risk: a Mendelian randomization study

BACKGROUND

Observational studies have linked childhood obesity with elevated risk of colorectal cancer; however, it is unclear if this association is causal or independent from the effects of obesity in adulthood on colorectal cancer risk.

METHODS

We conducted Mendelian randomization (MR) analyses to investigate potential causal relationships between self-perceived body size (thinner, plumper, or about average) in early life (age 10) and measured body mass index in adulthood (mean age 56.5) with risk of colorectal cancer. The total and independent effects of body size exposures were estimated using univariable and multivariable MR, respectively. Summary data were obtained from a genome-wide association study of 453,169 participants in UK Biobank for body size and from a genome-wide association study meta-analysis of three colorectal cancer consortia of 125,478 participants.

RESULTS

Genetically predicted early life body size was estimated to increase odds of colorectal cancer (odds ratio [OR] per category change: 1.12, 95% confidence interval [CI]: 0.98-1.27), with stronger results for colon cancer (OR: 1.16, 95% CI: 1.00-1.35), and distal colon cancer (OR: 1.25, 95% CI: 1.04-1.51). After accounting for adult body size using multivariable MR, effect estimates for early life body size were attenuated towards the null for colorectal cancer (OR: 0.97, 95% CI: 0.77-1.22) and colon cancer (OR: 0.97, 95% CI: 0.76-1.25), while the estimate for distal colon cancer was of similar magnitude but more imprecise (OR: 1.27, 95% CI: 0.90-1.77). Genetically predicted adult life body size was estimated to increase odds of colorectal (OR: 1.27, 95% CI: 1.03, 1.57), colon (OR: 1.32, 95% CI: 1.05, 1.67), and proximal colon (OR: 1.57, 95% CI: 1.21, 2.05).

CONCLUSIONS

Our findings suggest that the positive association between early life body size and colorectal cancer risk is likely due to large body size retainment into adulthood.

Colorectal cancer screening in Semarang, Indonesia: A multicenter primary health care based study

Colorectal cancer (CRC) is a major public health problem in Indonesia. It ranks among the top four cancers with high mortality rates. CRC screening is expected to improve early diagnosis that can reduce mortality and morbidity rate. Primary health care-based CRC screening in Indonesia has not yet been performed. This study was conducted to obtain information about prevalence, adenoma detection rate and public compliance for CRC screening in Semarang, Indonesia. This cross-sectional study was done across 10 primary health care centers in Semarang during April-October 2021. The screening method used Immunochromatography Faecal Occult Blood Tests (I-FOBT) as the primary test. Patients with positive I-FOBT result would be referred to Kariadi hospital for colonoscopy and histology examination. A total of 221 patients were included, 66.1% were female, mean age was 59.38 ± 7.48 years. Participation rate was 63%, 37 patients (16.7%) were I-FOBT positive, 26 patients (70.27%) underwent colonoscopy. Colonoscopy compliance rate was 70.27%. The colonoscopy results were haemorrhoid (30.8%), polyps (30.8%), malignancy (19.2%), colitis (7.7%), diverticulosis (7.7%), and normal (3.8%). The adenoma detection rate was 26.9%. BMI abnormality (overweight and obese) (OR 10.968; 95% CI 2.33-51.55) and family history of malignancy (OR 18.800; 95% CI 5.13-68.85) increased the risk of colorectal cancer and adenoma and respectively. The prevalence of I-FOBT positive in primary health care centers is high. The CRC screening program based on primary care should be considered. Public awareness education should be considered to increase colonoscopy compliance.

Association of childhood and adolescence obesity with incidence and mortality of adulthood cancers. A systematic review and meta-analysis

BACKGROUND

Prevalence and subsequent conditions of childhood and adolescent obesity are increasing. It has been seen that obesity in youth is associated with adulthood cancer. This systematic review and meta-analysis aimed to determine the pooled association of childhood obesity with cancers in adulthood.

METHODS

In this systematic review, international electronic databases such as Scopus, PubMed, Web of Science, and EMBASE were searched using relevant keywords until February 2022. All Cohort studies assessing the association of childhood and adolescent obesity (under 18 years old) with the incidence and mortality of all types of cancers were included. Two independent reviewers screened and carried out the quality assessment of included studies. Between-studies heterogeneity was assessed using the I squared and Cochran's Q tests. Random/fixed-effect meta-analyses were used to pool the appropriate effect sizes (Hazard ratios (HR)).

RESULTS

Overall, 46 studies were found to be relevant and were included in this study. Based on the random-effects model meta-analysis, childhood obesity increased the hazard of cancer incidence and mortality in adulthood by 33% (HR: 1.33, 95%CI (1.25, 1.41)) and by 28% (HR: 1.28, 95%CI (1.13, 1.42)), respectively. In the subgroups meta-analysis, the HR of childhood obesity and adulthood cancer incidence mortality in women was higher than in men (HR=1.39, 95%CI (1.25, 1.53) vs HR= 1.20, 95%CI (1.07, 1.32)) and (HR= 1.40, 95%CI (1.10, 1.69) vs HR=1.20, 95%CI (1.04, 1.36)) respectively.

CONCLUSION

This study found that obesity in childhood and adolescence is associated with a significant increase in the incidence and mortality of cancers in adulthood. Prevention of childhood obesity, in addition to its short-term beneficial effects, can reduce the burden of cancer in adulthood. The data sets of this study are present in the Tables of the current manuscript. Moreover this study was registered online in PROSPERO (registration code: CRD42022331958).

SYSTEMIC REVIEW REGISTRATION

https://www.crd.york.ac.uk/Prospero/, identifier CRD42022331958.

Energy balance-related factors in childhood and adolescence and risk of colorectal cancer based on KRAS, PIK3CA, and BRAF mutations and MMR status

KRAS mutations (KRAS_mut ), PIK3CA_mut , BRAF_mut , and deficient DNA mismatch repair (dMMR) have been associated with the Warburg effect. We previously reported differential associations between early-life energy balance-related factors (height, energy restriction, body mass index [BMI]) and colorectal cancer (CRC) subtypes based on the Warburg effect. We now investigated associations of early-life energy balance-related factors and the risk of CRC subgroups based on mutation and MMR status. Data from the Netherlands Cohort Study was used. KRAS_mut , PIK3CA_mut, BRAF_mut, and MMR status were available for 2349 CRC cases, and complete covariate data for 1934 cases and 3911 subcohort members. Multivariable-adjusted Cox regression was used to estimate associations of height, energy restriction proxies (exposure to Dutch Hunger Winter, Second World War, Economic Depression), and early adult BMI (age 20 years) with risk of CRC based on individual molecular features and combinations thereof (all-wild-type+MMR-proficient [pMMR]; any-mutation/dMMR). Height was positively associated with any-mutation/dMMR CRC but not all-wild-type+pMMR CRC, with the exception of rectal cancer in men, and with heterogeneity in associations observed for colon cancer in men (p-heterogeneity = 0.049) and rectal cancer in women (p-heterogeneity = 0.014). Results on early-life energy restriction proxies in relation to the risk of CRC subgroups did not show clear patterns. Early adult BMI was positively, but not significantly, associated with KRAS_mut colon cancer in men and with BRAF_mut and dMMR colon cancer in women. Our results suggest a role of KRAS_mut , PIK3CA_mut , BRAF_mut , and dMMR in the etiological pathway between height and CRC risk. KRAS_mut might potentially play a role in associations of early adult BMI with colon cancer risk in men, and BRAF_mut and dMMR in women.

The role of inflammatory miRNA-mRNA interactions in PBMCs of colorectal cancer and obesity patients

Introduction

Inflammation is a critical hallmark in obesity and colorectal cancer (CRC). This study aimed to investigate effective microRNA (miRNA)–messenger RNA (mRNA) interactions on inflammatory networks involved in obesity and CRC.

Methods

The literature searches were applied to identify genes expression reported on peripheral blood mononuclear cells (PBMCs) and/or blood of CRC subjects and to find inflammatory miRNA  in blood samples. Furthermore, bioinformatics analysis was utilized to find inflammatory miRNA:mRNA interactions of the genes. Finally, a case‐control study was set to investigate the expression of LAMC1 and GNB3 genes besides miR‐10b, miR‐506‐3p, miR‐150‐5p, and miR‐124‐3p in CRC and control subjects.

Results

The expression of LAMC1 gene in healthy control groups was associated with body mass index (BMI) (p < .05). The level of miR‐10b (p < .001), miR‐506 (p < .001), and miR‐124 (p <. 001) were significantly increased in PBMCs of CRC patients, while they were not associated with BMI. The level of miR‐150 was associated with BMI in healthy subjects (p < .05).

Conclusions

The changes in the level of miR‐506 and miR‐124 in CRC patients may be associated with the regulatory role of these miRNAs on LAMC1 expression. The LAMC1 may be related to BMI, however, more observational studies on other populations are needed.

Genetic Obesity Variants and Risk of Conventional Adenomas and Serrated Polyps

BACKGROUND

Higher body mass index (BMI) is associated with increased risk of colorectal cancer. How genetically predicted BMI may be associated with colorectal cancer precursors is unknown.

AIMS

Our objective was to quantify the association of genetically predicted and measured BMI with risk of colorectal cancer precursors.

METHODS

We evaluated the association of genetically predicted and measured BMI with risk of conventional adenomas, serrated polyps, and synchronous polyps among 27,426 participants who had undergone at least one lower gastrointestinal endoscopy in the Nurses' Health Study, Nurses' Health Study II, and Health Professionals Follow-up Study. Genetic risk score was derived from 97 BMI-related single nucleotide polymorphisms. Multivariable logistic regression evaluated each polyp subtype compared to non-polyps.

RESULTS

For conventional adenomas, the OR per 2-kg/m² increase was 1.03 (95% CI, 1.01-1.04) for measured BMI and 0.98 (95% CI, 0.88-1.10) for genetically predicted BMI; for serrated polyps, the OR was 1.06 (95% CI, 1.04-1.08) and 1.04 (95% CI, 0.90-1.20), respectively; for synchronous polyps, the OR was 1.10 (95% CI, 1.07-1.13) and 1.09 (95% CI, 0.89-1.34), respectively. Genetically predicted BMI was associated with synchronous polyps in women (OR = 1.37, 95% CI: 1.05-1.79).

CONCLUSION

Genetically predicted BMI was not associated with colorectal cancer precursor lesions. The confidence intervals were wide and encompassed those for measured BMI, indicating that null findings may be due to insufficient power.

Colon Cancer and Obesity: A Narrative Review

Obesity has played a crucial role in the pathogenesis of various cancers, including colorectal cancer (CRC). Obesity has shown to increase the blood levels of insulin, insulin-like growth factor-1 (IGF-1), leptin, resistin, inflammatory cytokines such as interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), monocyte chemoattractant protein-1 (MCP-1) which in turn acts via various signaling pathways to induce colonic cell proliferation and in turn CRC development. It has been shown that estrogen can prevent and cause CRC based on which receptor it acts. Obese patients have relatively low levels of ghrelin and adiponectin that inhibit cell proliferation which further adds to their risk of developing CRC. Obesity can alter the microbial flora of the gut in such a way as to favor carcinogenesis. Weight loss and good physical activity have been related to a reduced incidence of CRC; obese individuals should be screened for CRC and counseled about the importance of weight reduction, diet, and exercise. The best way of screening is using BMI and waist circumference (WC) to calculate the CRC risk in obese people. This study has reviewed the association between obesity and its pathophysiological association with CRC development.

Food processing groups and colorectal cancer risk in Morocco: evidence from a nationally representative case-control study

OBJECTIVE

The aim of this study was to investigate the association between the consumption of foods and drinks from different food processing categories using the NOVA classification and CRC risk among Moroccan adults.

METHODS

1453 cases and 1453 matched controls aged at least 18 years and recruited from the 5 greater Moroccan regions were interviewed by trained investigators about their habitual diet using a standardized food frequency questionnaire (FFQ). Foods were categorized according to their degree of processing by the NOVA classification. Intakes of each food processing group were categorized into tertiles based on the distribution of controls with the lowest tertile considered as the reference category. Multivariable conditional logistic regression models were used to assess the association between each group and CRC risk (Odds Ratio (OR) and 95% Confidence Intervals (CI)), taking relevant confounders into account.

RESULTS

High consumption of unprocessed or minimally processed foods (NOVA group 1) was significantly inversely (OR = 0.82, 95%CI = 0.72-0.93), while high consumption of ultra-processed foods and drink products (NOVA group 4) was significantly positively (OR = 1.40, 95% CI = 1.22-1.61) associated with CRC risk as compared to the lowest intake group. These results were similar for colon and rectum sub-sites.

CONCLUSION

This is the first study to evaluate the association between the NOVA classification groups and CRC risk in an African country. Our results suggest that the consumption of ultra-processed foods and drink products may be associated with an increased risk of developing CRC, but longitudinal studies are needed to confirm these results.

Review article: obesity and colorectal cancer

BACKGROUND

Obesity is a growing global public health problem. More than half the European and North American population is overweight or obese. Colon and rectum cancers are still the second leading cause of cancer death worldwide, and epidemiological data support an association between obesity and colorectal cancers (CRCs).

AIM

To review the literature on CRC epidemiology in obese subjects, assessing the effects of obesity, including childhood or maternal obesity, on CRC, diagnosis, management, and prognosis, and discussing targeted prophylactic measures.

METHOD

We searched PubMed for obesity/overweight/metabolic syndrome and CRC. Other key words included 'staging', 'screening', 'treatment', 'weight loss', 'bariatric surgery' and 'chemotherapy'.

RESULTS

In Europe, about 11% of CRCs are attributed to overweight and obesity. Epidemiological data suggest that obesity is associated with a 30%-70% increased risk of colon cancer in men, the association being less consistent in women. Visceral fat or abdominal obesity seems to be of greater concern than subcutaneous fat obesity, and any 1 kg/m² increase in body mass index confers more risk (hazard ratio 1.03). Obesity might increase the likelihood of recurrence or mortality of the primary cancer and may affect initial management, including accurate staging. The risk maybe confounded by different factors, including lower adherence to organised CRC screening programmes. It is unclear whether bariatric surgery helps reduce rectal cancer risk.

CONCLUSIONS

Despite a growing body of evidence linking obesity to CRC, many questions remain unanswered, including whether we should screen patients with obesity earlier or propose prophylactic bariatric surgery for certain patients with obesity.

The timing of adiposity and changes in the life course on the risk of cancer

Excess body weight has been established as a risk factor for at least twelve cancer sites, though questions remain as to the timing of associations for adiposity and cancer risk throughout the life course. We conducted a narrative review summarizing existing evidence to provide insights into the complex timing relationship between adiposity and risk of seven common obesity-related cancers. We considered five types of studies, including traditional epidemiologic studies examining adiposity at different time points, studies examining weight gain in specific life phases, studies examining weight loss over a period including from bariatric surgery, life course trajectory analysis, and Mendelian randomization studies. The results showed that lifetime excess body weight is associated with increased risk of cancers of endometrium, colorectum, liver, kidney, and pancreas. Early life obesity is one of the strongest risk factors for pancreatic cancer but less directly important than adult obesity for endometrial and kidney cancer. Interestingly, heavy weight during childhood, adolescence, and early adulthood is protective against pre- and postmenopausal breast cancer and possibly advanced prostate cancer. It is apparent that preventing weight gain later in adulthood would likely reduce risk of many cancers, including postmenopausal breast cancer, endometrial cancer, colorectal cancer (especially in men), liver cancer, kidney cancer, and probably advanced prostate cancer. Furthermore, weight loss even late in life may confer benefits for cancers of breast, endometrium, colorectum, and liver among patients with obesity, as mostly demonstrated by studies of bariatric surgery. Overall, maintaining a healthy weight throughout the life course will help prevent a large number of cancers.

Importance of ideal cardiovascular health metrics in the risk of colorectal cancer among people aged 50 years or older: a UK Biobank cohort study

OBJECTIVE

To explore the correlation between the ideal cardiovascular health metrics (ICVHMs) and the incidence of colorectal cancer (CRC) among people aged 50 years or older.

DESIGN

Prospective cohort study.

SETTING

The UK Biobank, a prospective cohort of middle-aged participants recruited between 2006 and 2010.

PARTICIPANTS

The study included 342 226 participants from the UK Biobank aged 50 years or older without prevalent cancer.

EXPOSURE

The ICVHMs consist of four behavioural factors (abstinence from smoking, ideal body mass index (BMI), physical activity at goal and consumption of healthy diet) and three cardiometabolic factors (untreated total cholesterol <200 mg/dL, untreated blood pressure <120/80 mm Hg and untreated fasting plasma glucose <100 mg/dL).

MAIN OUTCOMES

The outcome was ascertained by linkage to cancer and death registries using the International Classification of Diseases, Tenth codes C18-C20.

RESULTS

During a median follow-up time of 8.72 years, 3060 CRC cases were identified. Compared with the reference (participants with ICVHMs ≤2), the multivariable-adjusted HRs for subgroups with 3, 4, 5 and ≥6 ICVHM factors were 0.98 (95% CI 0.85 to 1.12), 0.90 (95% CI 0.77 to 1.02), 0.85 (95% CI 0.71 to 0.98) and 0.69 (95% CI 0.48 to 0.90), respectively. Among the seven ICVHM factors, lower BMI, healthier diet and ideal fasting plasma glucose were significantly associated with lower risk of CRC (HR: 0.86, 95% CI 0.78 to 0.95; HR: 0.92, 95% CI 0.84 to 0.99; HR: 0.90, 95% CI 0.80 to 0.99).

CONCLUSIONS

Adherence to the ICVHMs was associated with a lower risk of CRC among people aged 50 years or older. Among the seven ICVHM factors, BMI, diet and fasting plasma glucose played a more critical role in the prevention of CRC. These findings imply that adherence to ICVHMs should be encouraged to reduce the burden of cardiovascular disease as well as CRC.

Obesity-Associated Differentially Methylated Regions in Colon Cancer

Obesity with adiposity is a common disorder in modern days, influenced by environmental factors such as eating and lifestyle habits and affecting the epigenetics of adipose-based gene regulations and metabolic pathways in colorectal cancer (CRC). We compared epigenetic changes of differentially methylated regions (DMR) of genes in colon tissues of 225 colon cancer cases (154 non-obese and 71 obese) and 15 healthy non-obese controls by accessing The Cancer Genome Atlas (TCGA) data. We applied machine-learning-based analytics including generalized regression (GR) as a confirmatory validation model to identify the factors that could contribute to DMRs impacting colon cancer to enhance prediction accuracy. We found that age was a significant predictor in obese cancer patients, both alone (p = 0.003) and interacting with hypomethylated DMRs of ZBTB46, a tumor suppressor gene (p = 0.008). DMRs of three additional genes: HIST1H3I (p = 0.001), an oncogene with a hypomethylated DMR in the promoter region; SRGAP2C (p = 0.006), a tumor suppressor gene with a hypermethylated DMR in the promoter region; and NFATC4 (p = 0.006), an adipocyte differentiating oncogene with a hypermethylated DMR in an intron region, are also significant predictors of cancer in obese patients, independent of age. The genes affected by these DMR could be potential novel biomarkers of colon cancer in obese patients for cancer prevention and progression.

Exploring the Impact of the Obesity Paradox on Lung Cancer and Other Malignancies

Simple Summary

Studies have shown that obesity is associated with many adverse health effects, including worse cancer outcomes. Many studies paradoxically suggest a survival benefit for obesity in treatment outcomes of cancers such as non-small-cell lung cancer. This relationship is not seen in animal models. We hypothesize that this relationship is secondary to suboptimal quantification of adiposity, enhanced immunotherapy response, and variables such as sex, medications, and smoking status. There are many ways to measure and classify adiposity, but the ability to distinguish abdominal obesity is likely key in predicting accurate prognosis. There are many ways obesity impacts cancer treatment course from diagnosis to survivorship. In this paper, we aim to analyze the factors contributing to the obesity paradox and its effect on lung cancer. This can aid the treatment and prognosis of lung cancer and may support further research into obesity-specific impacts on this malignancy.

Abstract

There is a paradoxical relationship between obesity, as measured by BMI, and many types of cancer, including non-small-cell lung cancer. Obese non-small-cell lung cancer patients have been shown to fare better than their non-obese counterparts. To analyze the multifaceted effects of obesity on oncologic outcomes, we reviewed the literature on the obesity paradox, methods to measure adiposity, the obesity-related derangements in immunology and metabolism, and the oncologic impact of confounding variables such as gender, smoking, and concomitant medications such as statins and metformin. We analyzed how these aspects may contribute to the obesity paradox and cancer outcomes with a focus on lung cancer. We concluded that the use of BMI to measure adiposity is limited and should be replaced by a method that can differentiate abdominal obesity. We also concluded that the concomitant metabolic and immunologic derangements caused by obesity contribute to the obesity paradox. Medications, gender, and smoking are additional variables that impact oncologic outcomes, and further research needs to be performed to solidify the mechanisms.

Energy balance‐related factors in childhood and adolescence and risk of colorectal cancer expressing different levels of proteins involved in the Warburg‐effect

Early‐life (childhood to adolescence) energy balance‐related factors (height, energy restriction, BMI) have been associated with adult colorectal cancer (CRC) risk. Warburg‐effect activation via PI3K/Akt‐signaling might explain this link. We investigated whether early‐life energy balance‐related factors were associated with risk of Warburg‐subtypes in CRC. We used immunohistochemistry for six proteins involved in the Warburg‐effect (LDHA, GLUT1, MCT4, PKM2, P53, and PTEN) on tissue microarrays of 2399 incident CRC cases from the prospective Netherlands Cohort Study (NLCS). Expression levels of all proteins were combined into a pathway‐based sum score and categorized into three Warburg‐subtypes (Warburg‐low/‐moderate/‐high). Multivariable Cox‐regression analyses were used to estimate associations of height, energy restriction proxies (exposure to Dutch Hunger Winter; Second World War [WWII]; Economic Depression) and adolescent BMI with Warburg‐subtypes in CRC. Height was positively associated with colon cancer in men, regardless of Warburg‐subtypes, and with Warburg‐low colon and Warburg‐moderate rectal cancer in women. Energy restriction during the Dutch Hunger Winter was inversely associated with colon cancer in men, regardless of Warburg‐subtypes. In women, energy restriction during the Hunger Winter and WWII was inversely associated with Warburg‐low colon cancer, whereas energy restriction during the Economic Depression was positively associated with Warburg‐high colon cancer. Adolescent BMI was positively associated with Warburg‐high colon cancer in men, and Warburg‐moderate rectal cancer in women. In conclusion, the Warburg‐effect seems to be involved in associations of adolescent BMI with colon cancer in men, and of energy restriction during the Economic Depression with colon cancer in women. Further research is needed to validate these results.

Gender difference in metabolic syndrome and incident colorectal adenoma: A prospective observational study (KCIS No.42)

ABSTRACT

This community-based study aimed to elucidate whether there is a gender difference in the effect of metabolic syndrome (MetS) and its individual components on an elevated risk for incident colorectal adenoma.A prospective cohort study was conducted by enrolling 59,767 subjects aged 40 years or older between 2001 and 2009 in Keelung, Taiwan, to test this hypothesis, excluding those with a prior history of colorectal cancer and those with colorectal cancer diagnosed at the first screening. Cox proportional hazards regression models were used to assess the effect of MetS in terms of a dichotomous classification, each individual component and the number of components for males and females.Colorectal adenoma was present in 2.7% (n = 652) of male participants and 1.1% (n = 403) of female participants. The prevalence rate of MetS was 26.7% and 23.3% for males and females, respectively. The effect of MetS on colorectal adenoma was statistically significant and similar for the 2 genders, with an adjusted hazard ratio (aHR) of 1.33 (95% CI: 1.13-1.58) in males and 1.33 (95% CI: 1.06-1.66) in females after adjustment for confounders. However, MetS led to higher risk of advanced colorectal adenoma in men than in women. Regarding the effect of each component of MetS on colorectal adenoma, abnormal waist circumference and hypertriglyceridemia led to an elevated risk of colorectal adenoma in both genders. A rising risk of colorectal adenoma among females was noted in those with a moderately higher level of glycemia (100-125 mg/dL, aHR = 1.44, 95% CI: 1.12-1.85). Hypertriglyceridemia and high blood pressure were associated with an increased risk of advance colorectal adenoma in males.Both male and female subjects with MetS had a higher risk of colorectal adenoma. The contributions from individual components of MetS varied by gender. These findings suggest that the possible risk reduction of colorectal adenoma through metabolic syndrome-based lifestyle modifications may differ between genders.

Sex Differences in the Incidence of Obesity-Related Gastrointestinal Cancer

Cancer is the second leading cause of death worldwide, with 9.6 million people estimated to have died of cancer in 2018. Excess body fat deposition is a risk factor for many types of cancer. Men and women exhibit differences in body fat distribution and energy homeostasis regulation. This systematic review aimed to understand why sex disparities in obesity are associated with sex differences in the incidence of gastrointestinal cancers. Cancers of the esophagus, liver, and colon are representative gastrointestinal cancers, and obesity is a convincing risk factor for their development. Numerous epidemiological studies have found sex differences in the incidence of esophageal, liver, and colorectal cancers. We suggest that these sexual disparities are partly explained by the availability of estrogens and other genetic factors regulating inflammation, cell growth, and apoptosis. Sex differences in gut microbiota composition may contribute to differences in the incidence and phenotype of colorectal cancer. To establish successful practices in personalized nutrition and medicine, one should be aware of the sex differences in the pathophysiology and associated mechanisms of cancer development.

BMI May Be a Prognostic Factor for Local Advanced Rectal Cancer Patients Treated with Long-Term Neoadjuvant Chemoradiotherapy

OBJECTIVE

This study aims to develop feasible nomograms to predict the overall survival (OS) and cancer-specific survival (CSS) of the local advanced rectal cancer (LARC) patients who were treated with neoadjuvant chemoradiotherapy (nCRT) and operation.

METHODS

A total of 243 LARC patients undergoing nCRT followed by total mesorectal excision (TME) were enrolled. Preoperative clinical features and postoperative pathological characteristics were collected. A Cox regression analysis was performed, and Cox-based nomograms were developed to predict the OS and CSS. We assessed the predictive performance of the nomogram with concordance index and calibration plots.

RESULTS

A total of 243 patients were included with a median follow-up period of 46 months (range from 9 to 86 months). Cox regression analysis showed that low BMI (BMI < 18.5, HR= 21.739, P < 0.05), high level of preoperative CA19-9 (HR = 3.369, P = 0.036), high ypStage (HR = 19.768, P < 0.001), positive neural invasion (HR = 4.218, P = 0.026) and no adjuvant chemotherapy (HR = 5.495, P < 0.001) were independent predictors of poor OS. Age ≥70 (HR = 2.284, P <0.001), low BMI (BMI < 18.5, HR = 3.906, P < 0.05), positive preoperative CA19-9 (HR = 1.920, P = 0.012), high ypStage (HR = 5.147, P <0.001) and positive neural invasion (HR = 2.873, P = 0.022) were independent predictors of poor CSS. The predictive nomograms were developed to predict the OS and CSS with a C-index of 0.837 and 0.760. Good statistical performance on internal validation was shown by calibration plots.

CONCLUSION

In conclusion, this study demonstrated that BMI was an independent prognostic factor for OS and CSS in LARC patients treated with nCRT followed TME. A nomogram incorporating BMI, neural invasion, pre-CA19-9, ypStage, age, and adjuvant chemotherapy could be helpful to predict the OS and CSS.

Investigation of Leptin and its receptor (LEPR) for single nucleotide polymorphisms in colorectal cancer: a case-control study involving 2,306 subjects

Single nucleotide polymorphisms (SNPs) in the genes coding for leptin (LEP) and its receptor (LEPR) might regulate energy balance and be implicated in the development of colorectal cancer (CRC). In the present investigation, 1,003 CRC cases and 1,303 matched controls was compared. Five functional SNPs in LEP and LEPR genes were chosen to evaluate the correlation of these chosen SNPs with CRC susceptibility. We used the SNPscan^TM genotyping assay to genotype LEP and LEPR SNPs. A significantly decreased risk of CRC was found to be associated with the LEPR rs6588147 polymorphism (GA vs. GG: crude P=0.007 and GA/AA vs. GG: crude P=0.018). With adjustments for risk factors (e.g. age, gender, drinking, BMI and smoking), these associations were not changed. In subgroup analyses, the association of LEP rs2167270 with a decreased risk of CRC was found in the ≥61 years old subgroup. For LEPR rs1137100, the association of this SNP with an increased susceptibility of CRC was found in the BMI <24 kg/m² subgroup. In subgroup analyses for LEPR rs6588147, we identified that this locus also decreased the susceptibility of CRC in the male subgroup, <61 years old subgroup, never smoking subgroup and never drinking subgroup. For LEPR rs1137101, the relationship of this polymorphism with a decreased susceptibility to CRC was found in the never drinking subgroup. In summary, the present study highlights that LEPR rs6588147, rs1137101 and LEP rs2167270 may decrease the risk of CRC. However, LEPR rs1137100 is associated with susceptibility to CRC. Further case-control studies with larger sample sizes should be conducted to validate our findings.

Yogurt consumption and colorectal polyps

Diet modifies the risk of colorectal cancer (CRC), and inconclusive evidence suggests that yogurt may protect against CRC. We analysed the data collected from two separate colonoscopy-based case-control studies. The Tennessee Colorectal Polyp Study (TCPS) and Johns Hopkins Biofilm Study included 5446 and 1061 participants, respectively, diagnosed with hyperplastic polyp (HP), sessile serrated polyp, adenomatous polyp (AP) or without any polyps. Multinomial logistic regression models were used to derive OR and 95 % CI to evaluate comparisons between cases and polyp-free controls and case-case comparisons between different polyp types. We evaluated the association between frequency of yogurt intake and probiotic use with the diagnosis of colorectal polyps. In the TCPS, daily yogurt intake v. no/rare intake was associated with decreased odds of HP (OR 0·54; 95 % CI 0·31, 0·95) and weekly yogurt intake was associated with decreased odds of AP among women (OR 0·73; 95 % CI 0·55, 0·98). In the Biofilm Study, both weekly yogurt intake and probiotic use were associated with a non-significant reduction in odds of overall AP (OR 0·75; 95 % CI 0·54, 1·04) and (OR 0·72; 95 % CI 0·49, 1·06) in comparison with no use, respectively. In summary, yogurt intake may be associated with decreased odds of HP and AP and probiotic use may be associated with decreased odds of AP. Further prospective studies are needed to verify these associations.

Linking Obesity with Colorectal Cancer: Epidemiology and Mechanistic Insights

The incidence of obesity and colorectal cancer (CRC) has risen rapidly in recent decades. More than 650 million obese and 2 billion overweight individuals are currently living in the world. CRC is the third most common cancer. Obesity is regarded as one of the key environmental risk factors for the pathogenesis of CRC. In the present review, we mainly focus on the epidemiology of obesity and CRC in the world, the United States, and China. We also summarize the molecular mechanisms linking obesity to CRC in different aspects, including nutriology, adipokines and hormones, inflammation, gut microbiota, and bile acids. The unmet medical needs for obesity-related CRC are still remarkable. Understanding the molecular basis of these associations will help develop novel therapeutic targets and approaches for the treatment of obesity-related CRC.

Revisiting the impact of lifestyle on colorectal cancer risk in a gender perspective

Colorectal cancer (CRC) is a leading cause of cancer-related mortality in the world. Patterns and trends in CRC incidence and mortality correlate with increasing adoption of Western lifestyles and with the overweight/obesity epidemic. Both genetic background and a range of modifiable environmental/lifestyle factors play a role in CRC etiology. Among these the links of body weight, dietary patterns and physical activity (PA) behavior with CRC risk are some of the strongest for any type of cancer, with a different impact in women and men. Nonetheless, gender disparities still represent a neglected aspect of CRC management. This review sheds light on gender-related association of obesity and different dietary/PA habits with CRC risk, highlighting the importance of lifestyle modifications in the prevention of this neoplastic disease. In this scenario, intervention studies are strongly recommended to define the most effective dietary/PA regimens for primary prevention of cancer in women and men.